Question

if b/a=2/5, what is the value of 2 (a/b)

Answer 1

$\dfrac{b}{a}=\dfrac{2}{5}\to\dfrac{a}{b}=\dfrac{5}{2}\ \ \ |\cdot2\\\\2\left(\dfrac{a}{b}\right)=2\cdot\dfrac{5}{2}\\\\2\left(\dfrac{a}{b}\right)=5$

Answer: 2(a/b) = 5